1. Field of the Technology
The present technology relates to a solar cell array and a solar cell module employing the solar cell array, and more particularly, it relates to a solar cell array having a protective diode and allowing simple connection between solar cells and a solar cell module employing this solar cell array.
2. Description of the Background Art
FIGS. 9 to 12 show exemplary conventional flexible solar cells. In one of the conventional solar cells, an n-type electrode 52 is formed on the surface of a single-crystalline thin film layer 51, as shown in FIGS. 9 and 10. Single-crystalline thin film layer 51 is formed by epitaxially growing an element layer on a semiconductor substrate and thereafter separating the semiconductor substrate and the epitaxially grown element layer from each other. A metal thin film 53 having a thickness of not more than 100 μm is formed on the lower surface of single-crystalline thin film layer 51 as a holding material for supporting electrode 52 or the semiconductor layer. Single-crystalline thin film layer 51 has a thickness of not more than 50 μm, for example, and includes at least one p-n junction. On metal thin film 53, a p-type electrode pad 54 is formed on the same surface as electrode 52. In order to serially or parallelly electrically connect such solar cells with each other, interconnectors 56 are electrically connected to electrode 52 and electrode pad 54 by parallel gap welding or the like.
This solar cell is abundant in flexibility, due to the extremely thin semiconductor layer. A protective resin film of polyimide or the like may be bonded to the back surface of this solar cell. In order to prepare a solar cell array, a plurality of such solar cells are serially or parallelly connected with each other, a diode serving as a protective element is parallelly connected to the solar cells, and sealed with adhesives such as transparent resin films 57 and silicone resin films 56.
On the other hand, a connecting structure shown in FIGS. 11 and 12 is known as a general technique of connecting a diode to a solar cell in order to protect the device (refer to U.S. Pat. No. 6,034,322, for example). This solar cell is formed on a substrate, and has no flexibility. In the connecting structure shown in FIGS. 11 and 12, a diode 59 in the form of a triangular flat plate is set on a corner 58a provided on a solar cell 58 in order to effectively utilize a circular crystalline substrate. At least one corner of solar cell 58 is partially removed to form a beveled edge, so that diode 59 is set on corner 58a. 
In solar cell 58 having built-in diode 59, a diode connector 60 is bonded to a front electrode 61 of solar cell 58 and that of diode 59 by a method such as parallel gap welding or the like respectively, while another diode connector 62 is bonded to a rear electrode 63 of solar cell 58 and that of diode 59 by a method such as parallel gap welding or the like respectively. Thus, solar cell 58 and diode 59 are electrically parallelly connected with each other, so that solar cell 58 can be prevented from breakage even if a reverse voltage is applied to solar cell 58.
Conventional solar cell 58 having built-in protective diode 59 is connected with protective diode 59 by diode connectors 60 and 62 having specific shapes for the connection between solar cell 58 and protective diode 59, and hence the number of bonded points is increased, the time (assembly time) for building protective diode 59 into solar cell 58 is increased, and reliability is reduced. Particularly on the surface of solar cell 58, rectangular front electrode 61 is provided around the outer periphery of solar cell 58, and it is difficult to bond diode 59 by welding or the like in response to the position of front electrode 61, and the assembly time is increased due to the increased number of bonded points.
Further, the front and rear sides of protective diode 59 and solar cell 58 are simultaneously connected with each other by connectors 60 and 62, and hence the process time is disadvantageously increased. If a diode is connected to the back surface of the flexible solar cell with a connector, on the other hand, a step is caused due to connectors provided on both surfaces of the solar cell. Therefore, the solar cell may be broken due to this step, and the process time for handling the solar cell in welding is increased as compared with that for a rigid solar cell formed on a substrate.